Process for recovering manganese from ore



Patented v Mar. 13, 1934 PROCESS FOR. RECOVERING MANGANESE FROM ORE Fred D. De Vaney and Julius Bruce Clemmer, Rolla, Mo., assignors to The Reclamation Company, St. Paul, Minn., a corporation of Delaware No Drawing. Application March 31, 1930,

Serial No. 440,618

Claims.

This invention relates to a process for concentrating ores of manganese by froth flotation.

One of the objects of this invention is to provide a process whereby manganese ores, and more particularly low grade ores may be effectively and economically concentrated by flotaion.

Another object is to apply a collecting agent having a preferential affinity for manganese 10 ores.

Another object is to carry on the process in such a manner as to. secure economical and effective separation of: manganese ores from their gangues.

Another object is to effect a preliminary separation of another ore component associated with the manganese, in order to effect subsequent separation of the manganese by froth flotation.

Further objects will appear from the detailed description in which will be described a number 'of embodiments of this invention; it will be understood, however, that this invention is susceptible of various other embodiments.

We have discovered an economical and effi- 6 cient means of concentrating by froth flotation the low-grade ores in which the manganese is present as the carbonate, rhodochrosite; or the ox des, manganite, pyrolusite, psilomelane, or

hausemanite. In our flotation process the man 0 ganese minerals are segregated in a froth, produced as hereinafter stated, and is removed from the flotation machine. The gangue material, since it does not'form a froth in our process, is left behind in the flotation cell to be later removed as tailings. A separation is thereby obtained between the manganese minerals and the gangue material.

Ores in which there is but a slight difference of specific gravity between mineral and gangue do not respond readily to separation by gravity 1 concentration methods such as jigging and tabling. Flotation, depending as it does on other physical properties than that of specific gravity, is especially applicable to ores of this type. In many ores the mineral and gangue are locked at the tabling and jigging sizes commonly employed. This locking defeats separation by gravity methods. Upon grinding these ores to flotation size they are in many cases fairly well liberated, making possible a fair separation by col flotation. Ores containing soft manganese minerals, such as pyrolusite, slime badly when treated on jigs and tables, and much of the mineral is lost in the slime. This slime forms an ideal flotation feed and lends itself well to our process.

After a number of experiments a satisfactory method of concentrating these ores by froth, flotation was worked out by us. Briefly stated the preferred procedure consists in grinding the 0 ore to approximately 10;) mesh, or finer, and then treating the comminuted ore in a flotation machine of standard design. The flotation reagent which we employ in our process depends upon the nature of the ore to be treated. In general 5 we have used either a fatty acid, such as oleic, palmitic, or stearic, or a fatty acid soap, such as sodium oleate, sodium palmitate, or sodium stearate, or a combination of the two, in the presence of a frothing agent such as pine oil or cresylic acid. It will be observed that pine oil and cresylio acid are at leastpartially soluble in water. In the flotation of the oxide minerals of manganese we have found that the best results are obtained when we employ an alkaline silicate and an alkaline hydroxide or carbonate, in ad-' dition to the above named reagents. The alkaline silicate disperses the ore pulp and allows a selective flocculation and. flotation of the manganese ore mineral particles; while the alkaline so hydroxide or carbonate maintains the pulp nonacid and preferably alkaline. The quantity of fatty acid or fatty acid soap which is required in our process is small. The success of our process depends on the fact that small quantities 35 of the fatty acids or fatty acid soaps selectively flocculate and float manganese minerals rather than the gangue minerals in a properly conditioned flotation pulp. Any increase in the amount of the fatty acids or fatty acid soaps used over the minimum amount required tends to destroy the Selectivity of our process. For the average manganese ore the amount of the fatty acid or fatty acid soap required will not, exceed four pounds per ton of crude ore.

We are aware that oxides of manganese have previously been separated from their gangues by flotation. In those processes, however, the froth produced is a mass of particles cohering by oil adhesion and lightened by entangled bubbles. 10D

Large amounts of reagents are necessary in such processes, the exact amounts depending upon the quantity of concentrates to be collected. Generally, it may be said that the proportion of reagent exceeds ten per cent by weight of the minerals to be floated. On the other hand, in our process the minerals adhere to the walls of bubbles which are formed in the pulp, and, as above stated, the amount of fatty acid or fatty acid soap is relatively small, not exceeding about four pounds per ton of crude ore treated.

The Butte district of Montana contains large quantities of manganese ore in the form of the carbonate, rhodochrosite, which is associated with rhodonite, quartz, and small quantities of lead and zinc in the form of sulphides. In the concentration of rhodochrosite ores which contain the manganese silicate, rhodonite, our flotation process has decided advantages over straight gravity and high intensity magnetic processes. Rhodonite, being a silicate, must be largely eliminated from the manganese concentrate since its presence tends to make the silica content too high to permit the product to be used for the manufacture of ferromanganese. The specific gravities of rhodochrosite and rho donite are so close together as to make it impossible to make a good separation between them by tables. Flotations experiments made by us on ores containing rhodochrosite and rhodonite have definitely proved that a good separation can be made by our process. The rhodochrosite floats while the silicate, rhodonite, goes into the tailing. A representative sample of the carbonate ore from the Butte district requiring concentration was obtained by us and was found to be about one-half quartz; some lead, zinc, and iron sulphides were also present. The sample had a tenor of about twenty percent manganese.

On these mixed ores we found that the sulphides could be recovered in a separate froth by the use of flotation reagents now in common use, such as xanthate, copper sulphate, and pine oil; and that the manganese carbonate, rhodochrosite, could be subsequently segregated in a second froth by the addition of a fatty acid or a fatty acid soap, and a frothing agent such as pine oil or cresylic acid. The quartz in the ore was little affected by the reagents used, and most of it passed into the tailing. The rougher concentrate, consisting of rhodochrosite and some entrained quartz was cleaned by being re-floated in the flotation cell.

The sulphide concentrate made on a typical run by us had a tenor of 8.1 percent lead, 18.4 percent zinc, 21.3 percent iron, and 3.0 percent manganese: Less than 1 percent of all the manganese was entrained in the sulphide concentrate. The by-product value of this sulphide concentrate, due to its lead and zinc content, should yield a revenue of some importance.

The cleaner concentrate made by our flotation process contained 67.7 percent of all the manganese and assayed 41.55 percent manganese. The rougher tailing had a tenor of less than 5 percent manganese and contained 10.8 percent of the total manganese in the sample. The cleaner tailing or middling had a tenor of 27.35 percent manganese and represented 31.7 percent of the total manganese in the feed. In plant operation the amount of manganese recovered in the concentrate is increased by part of the manganese in the cleaner tailing or middling; individual tests by us have shown that this product is amenable to further cleaning: The finished concentrate contained 6.9 percent insoluble matter, while the rougher tailing was 89.8 percent insoluble. These results show a decided selectivity.

The reagents used in a typical test in terms of pounds per ton of crude rhodochrosite ore containing in addition to manganese in carbonate form also sulphides of lead and zinc are as follows:

Pound Copper sulphate 0.5 Sodium ethyl xanthate 0.2 Pine oil 0.4 Crude sodium oleate 1.0

The copper sulphate and xanthate are used for the first froth to float the sulphides while the oleate is used for the second froth to float the manganese ore.

The results of a typical test on a soft ore, in which the manganese mineral is primarily the oxide, pyrolusite are as follows:

From the ore which contained 25.3 percent manganese and 54 percent insoluble material, a finished concentrate was produced which contained 56 percent manganese and accounted for over 91 percent of the total manganese in the sample. The rougher tailing, which is discarded, had a tenor of less than 2 percent manganeseless than 4 percent of the total manganese. The cleaner tailings, or middlings, had a tenor of 16.7 percent manganese and accounted for approximately 5 percent of the total manganese. In the plant the cleaner tailing, or middling, would be returned to the flotation machine, with the result that the manganese which it contains would eventually be recovered. By following our method, over 96 percent of the total manganese in the sample is recoverable by flotation. The finished concentrate contained' 4 percent of insoluble material and accounted for Pounds Pine oil 0. 12 Oleic acid .21 Sodium silicate 2.50 Sodium carbonate 2.50

The above combination of reagents was satisfactory on all ores in which the manganese was present as the oxide, such as psilomelane, hausmanite, manganite, or pyrolusite. The quantity of the individual reagent required varies somewhat with the ore treated, but is not far from the figures given in the foregoing charge. Other reagents of similar characteristics to those given have been investigated. With certain ores other fatty acids or fatty acid'soaps give better results than oleic acid. For best results the reagent charge must be adapted, to each ore treated.

A point which may be well brought out at this time is the effect of temperature upon the flotation of manganese oxides. When the fatty acids, such as oleic, stearic, or palmitic, are used as collectors, it has been found that heating the pulp to a temperature exceeding the melting point of the acid decreases the amount of reagent required and materially speeds up our flotation process. The grade of the concentrates and the recovery is improved by floating in a hot pulp. We have found that a high pulp density is also beneficial in improving the results.

The employment of our flotation process in the concentration of manganese ores offers great possibilities. Our process is especially applicable to the concentration of the carbonate ores. With oxide ores its application should be especially valuable in concentrating those ores requiring fine grinding, if a high-grade product is to be made, and in handling ores containing soft manganese minerals which slime badly, causing excessive losses if an attempt is made to jig or table them.

It will be understood that the term fatty acid is used descriptively rather than limitatively to include the salts of such acid or rather the fatty acid soaps, a number of which have been heretofore referred to. The words a substantial amount of an electrolyte are to be construed as meaning the amount of electrolyte in excess of that found naturally in the water which is used in the pulp. It will, furthermore, be understood that certain features, operations and sub-combinations are of utility and may be employed without reference to other features, operation and sub-combinations; that is contemplated by and-is within the scope of the appended claims. It is further obvious that various changes may be made in details and operations, within the scope of the appended claims, without departing from the spirit of this invention; it is, therefore, to be understood that this invention is not to be limited to the specific details and operations described.

Having'thus described the invention, what is claimed is:

l. The process of concentrating non-sulfid manganese ores by a froth flotation process, comprising, mixing with a pulp of such an ore and its gangue, a small proportion of a frothing agent and bringing bubbles into contact with the particles so as to produce a manganese-orebearing froth consisting of a mass of bubbles with mineral particles adhering to the walls thereof, and separating the froth from the 3. 'The process of concentrating manganese.

ores by flotation, comprising, mixing with an alkaline pulp of a non-sulfid manganese ore and its gangue, a small proportion 'of a fatty ,a manganese-ore-bearing froth which separates from the gangue.

5. The process of concentrating manganese ores by flotation,'comprising, mixing with an alkaline pulp of a manganese ore and its gangue, a small proportion of a fatty acid while the pulp is maintained above-normal temperature and bringing bubbles into contact with the .particles so as to produce a manganese-orebearing froth which separates from the gangue.

6. The process of concentrating manganeseoxide ores by flotation, comprising, mixing with an alkaline pulp of a manganese-oxide ore and its gangue, a small proportion of a flotation reagent containing a fatty acid radical and bringing bubbles into contact with the particles so as to produce a manganese-oxide-ore-bearing froth which separates from the gangue.

'7. The process of concentrating manganese carbonate ores by froth flotation, comprising lecting agent having a preferential aflinity for the manganese ore and bringing bubbles into contact with the particles so as to produce a mainganese-ore-bearing froth which separates from the gangue.

9. The process of concentrating ores containing non-sulfid manganese in association witha sulfid ore component, comprising, preliminarily separating the sulfid component by flotation, mixing with the remaining pulp a small percentage of a fatty acid and bringing bubbles into contact with the particles so as to produce a manganese-ore-bearing froth which separates from the gangue.

10. The process of concentrating manganese ores by flotation, comprising, mixing with a pulp of a manganese ore and its gangue, such pulp containing a substantial amount of an alkaline electrolyte, a. flotation reagent containing a fatty acid radical, and bringing bubbles into contact with the particles so as to produce a manganese-ore-bearing froth which separates from the gangue.

11. The process of concentrating a non-sulfid manganese ore, comprising, forming a pulp of such ores containing a substantial amount of an electrolyte, adding a frothing agent, and bringing bubbles into contact with the particles of the pulp until a manganese-ore-bearing froth is formed, and removing said froth.

12. A process of concentrating a non-sulfid manganese ore, comprising forming an alkaline pulp of such ore, adding a flotation reagent containing a fatty acid radical and a frothing agent containing water soluble constituents, and bringing bubbles into contact with the particles of the pulp .until a manganese-ore-bearing froth is formed, and removing said froth.

13. The process of concentrating non-sulfid manganese ores bya froth flotation process, comprising, mixing with the pulp of such an ore and its gangue, a flotation reagent containing a 50 fatty acid radical, such reagent comprising not more than one half of one percent, by weight; of the ore and gangue treated, pine oil,"an electrolyte; and a dispersing agent, and bringing bubbles into contact with the particles so as to produce a manganese-ore-bearing froth which separates from the gangue.

14. The process of concentrating non-sulfid 1 manganese ores by a froth flotation process,

comprising, mixing with' the pulp of such an ore and its ganguefa flotation reagent containing a fatty acid radical, such reagent comprising not more than one half of one percent, by weight, of the ore and gangue treated, pine oil, and a dispersing agent,'and bringing bubbles into contact with the particles so as to produce a manganese-ore-bearing froth whichseparates from the gangue.

15. The process of concentrating non-sulfld manganese ores by a froth flotation process, comprising, mixing with the pulp of such an ore and its gangue, a flotation reagent containing a fatty acid radical, such reagent comprising not more than one half of one percent, by weight, of the ore and gangue treated, and pine oil, conditioning the pulp to render the same alkaline, and bringing bubbles into contact with the particles so as to produce a manganese-orebearing froth which separates from the gangue.

16. The process of treating ores containing nonsulfid manganese and other constituents comprising, subjecting the ore to a preliminary treatment to remove a part of the constituents to increase the proportion of ncn-sulfid manganese in the remainder, and subjecting such remainder to a froth flotation process comprising mixing with the pulp of such remainder a flota= tion reagent containing a fatty acid radical and a frothing agent containing water soluble constituents and bringing bubbles into contact with the particles so as to produce a manganesebearing froth which separatesfrom the gangue.

17. The process of concentrating oxide ores of manganese by a froth flotation process, comprising, mixing with the pulp of such an are and its gangue a flotation reagent containing a fatty acid radical, such reagent comprising not more than one half of one percent, by weight, of the ore and gangue treated, pine oil, an alkaline silicate, and a conditioning agent to secure alkalinity, and bringing bubbles into contact with the particles so as to produce a manganese-oxide-bearing froth which separates from the gangue.

18. The process of concentrating oxide' ores of manganese by a froth flotation process, comprising, mixing with the pulp of such an ore and its gangue a flotation reagentf'containing a fatty acid radical, such reagent comprising not more than one half of one percent, by weight of the ore and gangue treated, pine oil, and an alkaline silicate, and bringing bubbles into contact with the particles so as to produce a manganese-oxide-bearing froth which separates rom the gangue.

19. The process of concentrating non-sulfid manganese ore by a froth flotation process, comprising mixing with a pulp of such an ore and its gangue a small quantity of pine oil and a small porportion of a flotation reagent containing a fatty acid soap, and bringing bubbles into contact with. the particles so as to produce a manganese ore-bearing froth consisting of a mass of bubbles with the particles adhering to the walls thereof and separating the froth from the gangue.

20. The process of concentrating non-sulfld manganese ore by a froth flotation process comprising mixing with the pulp of such an ore and its gangue a small quantity of pine oil, a small quantity of a flotation reagent containing a fatty acid, and a relatively larger quantity of sodium silicate and of sodium carbonate, and bringing bubbles into contact with the particles so as to produce a manganese ore bearing froth consisting of a mass of bubbles with the particles adhering to the walls thereof and separating the froth from the gangue.

FRED D. DE VANEY. JULIUS BRUCE CLEMMER. 

